Fluid-blast circuit interrupters having improved arc splitter structure



C. F. CROME'R FLUID-BLAST CIRCUIT INTERRUPTERS HAVING Dec. 13, 1966IMPROVED ARC SPLITTER STRUCTURE 4 Sheets-Sheet 1 Filed Sept. 18, 1964 8i i l wm vm Dec. 13, 1966 c. F. CROMER FLUID-BLAST CIRCUIT INTERRUPTERSHAVING "IMPROVED ARC SPLITTER STRUCTURE 4 Sheets-Sheet 2 Filed Sept. 18,1964 vDec. 13, 1966 c. F. CROMER 3,291,949

I FLUID-BLAST CIRCUIT INTERRUPTERS HAVING IMPROVED ARC SPLITTERSTRUCTURE Filed Sept. 18, 1964 4 SheetsSheet 3 WITNESSES 1 INVENTORyo-fig, Cfiorles F. Cromer ATTORNEY Dec. 13, 1966 t CROMER 3,291,949

FLUID-BLAST CIRCUIT INTERRUPTERS HAVING IMPROVED ARC SPLITTER STRUCTUREFiled Sept. 18, 1964 4 Sheets-Sheet 4 FIG. 5.

United States Patent Filed Sept. 18, 1964, Ser. No. 397,512 14 Claims.(Cl. 200-148) This invention relates, in general, to circuitinterrupters of the fluid blast type, and, more particularly, to suchtypes of circuit interrupters having improved arc-splitter structures.

The ability of a circuit interrupter to withstand high rates of rise ofrecovery voltages in alternating-current systems is proportional to thearc voltage at current zero. In other words, if a circuit interrupter isto withstand higher rates of rise of recovery voltages, the arc voltagemust be increased at current zero. The means for increasing the arcvoltage at current zero, however, should not jeopardize other criticalareas, such as by bridging the contacts of the circuit interrupter withsolid insulation when the contacts are in their open position, whichwould introduce the hazards of creepage. Any means for increasing thearc voltage must maintain an isolating gap between the contacts in theiropen position.

Accordingly, it is an object of this invention to provide a new andimproved fluid-blast circuit interrupter having an improved interruptingstructure.

Another object of the invention is to provide a new and improved circuitinterrupter which provides a high are voltage at current zero.

A further object of the invention is to provide a new and improvedcurrent interrupter which provides a high are voltage at current zero,and which has an isolating gap between its contacts when they are intheir opencircuit position.

Still another object of the invention is to provide a new and improvedfluid-blast circuit interrupter which has an improved interruptingstructure capable of withstanding high rates of rise of recoveryvoltages and which generates the fluid-blast by pressure-generatingcontacts disposed within a pressure chamber, which operatesimultaneously with the interrupting contacts.

Another object of the invention is to provide a new and improvedfluid-blast high-voltage circuit interrupter having pressure-generatingand interrupting contacts, in which the movable portions of thepressure-generating and interrupting contacts are serially related toform a partial loop.

Briefly, the present invention accomplishes the abovecited objects byproviding a live-tank type of circuit interrupter supported by suitableinsulating supports, in which is disposed an improved interruptingstructure. The fluid blast is generated within a pressure chamberdisposed within each tank of the circuit interrupter, withpressuregenerating contacts disposed within the pressure chamber. Themovable portions of the pressure-generating contacts are seriallyrelated and operate simultaneously with the movable portions of theinterrupting contacts. The serially-related movable contacts provide aloop effect which forces the are generated between the interruptingcontacts to move to the outside of the loop. Splitter-type interrupters,which provide a high are voltage at current zero, are mounted remotely,such as on one of the tank walls, and are disposed such that the arcmoves against the splitter plates by the loop effect. The fluid blast isdirected to force the are into the splitters, lengthening and coolingthe arc and increasing the arc voltage. By mounting the splitterinterrupter remotely from the interrupter contact assembly, solidinsulation, with its creep hazards, is not permitted to bridge theinterrupter contacts, thus allowing an isolation gap to be established3,291,949 Patented Dec. 13, 1966 between the interrupter contacts whenthey are in their open-circuit position.

Another embodiment of the invention combines the splitter-typeinterrupter with the orifice-type interrupter, obtaining the advantagesof both types of interrupters, and still providing the desirableisolating gap between the interrupting contacts while they are in theiropen-circuit position.

Further objects and advantages of the invention will become apparent asthe following description proceeds, and features of novelty whichcharacterize the invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of the invention, reference may be had to theaccompanying drawings, in which:

FIGURE 1 is an end elevational view of a three-phase, high voltage,fluid-blast circuit interrupter of the type which may utilize theteachings of this invention;

FIG. 2 is a side elevational view of one of the poleunits of the circuitinterrupter shown in FIG. 1;

FIG. 3 is a vertical sectional view taken through one of the live-tankinterrupting structures of FIGS. 1 and 2,

with the contact structure shown in the open-circuit position,illustrating one embodiment of the invention;

FIG. 4 is a fragmentary view similar to that of FIG. 3, but the contactstructure shown in the closed-circuit position;

FIG. 5 is a vertical sectional view taken through a modified-type oflive-tank interrupting structure with the contact structure being shownin the open-circuit position, illustrating another embodiment of theinvention; and,

FIG. 6 is a fragmentary view of the contact structure shown in FIG. 5,with the contacts shown in the closedcircuit position.

Referring now to the drawings, and to FIGS. 1 and 2 in particular, thereis shown a three-phase circuit-interrupting assemblage 10, typical ofthe type which may utilize circuit-interrupting structures constructedaccording to the teachings of this invention. The circuit-interruptingassemblage 10 may have pole-units 12, 14 and 16 mounted upon anangle-iron frame 18, with each poleunit having two or more similarserially-related interrupting portions, if desired. The frame 18 is atground potential and may be disposed upon a base 20, formed of concreteor other suitable material. An enclosure 22, for the operatingmechanism, may be mounted upon the frame 18, and may house any suitableoperating mechanism 24, such as hydraulic, pneumatic orelectric-solenoid.

The mechanical linkage extending from the operating mechanism 24 to thecircuit-interrupting units 26 may include a reciprocally-operable rod28, as shown in FIG. 2, extending upwardly from the operating mechanism24 through a housing tube 30, where it is pivotally connected to one endof a bell-crank lever 32. The bell-crank lever 32 is keyed to anoperating shaft 34 extending in opposite directions from the bell-cranklever 32. The rotatable operating shaft 34 is keyed to a pair of crankarms 36, which effect reciprocal horizontal movement of a pair ofoperating rods 38, shown in FIG. 1, which extend along the upper portionof frame 18 below insulating supporting columns 40, which are used tosupport the circuit-interrupting units 26. The operating rods 38 arepivotally connected to bell-cranks 42 pivotally mounted on shafts 44.The operating shafts 44 have crank-arms 46, to which insulatingoperating rods 48 are pivotally attached. The insulating operating rods48 extend upwardly through the insulating supporting columns 40, andtheir reciprocal operation effects the opening and closing movementsrequired by the movable portions of the contact structures associatedwith each of the circuitinterrupting units 26, which will be describedin more detail hereinafter. It is to be understood that the pa-rticularoperating arrangement and sequence described is illustrative only. Anyoperating arrangement for effecting the opening and closing movement ofthe contact structures associated with the interrupting units 26 will besuitable.

Each interrupting unit 26 includes a pressurized metallic enclosure, orhousing 50, and a pair of terminal bushings 52 and 54 having terminals56 and 58, respectively, disposed at their outer end portions. Thenumber of interrupting units 26, serially connected to form eachpole-unit, depends upon the operating voltage, with two interruptingunits 26, connected by a conductor 60, being shown in FIG. 2 forpurposes of illustration. Using two interrupting units 26, theelectrical circuit for the poleunit 16 would enter terminal 56 from lineL1, traverse the interior of bushing 52 into the interrupting unit 26,and out of unit 26 through bushing 54 to terminal 58. The circuit thencontinues in a similar manner through the other serially-connectedinterrupting unit 26.

As shown in FIG. 2, a pair of cylindrical support members 62 aresecured, by welding or by any other suitable means, to the housing 50 ofinterrupting unit 26. Each support member 62 includes a flange 64, whichaligns and supports the flange member 66 associated with each of theterminal bushings 52 and 54. Terminal bushings 52 and 54 may beconstructed in a conventional manner, with each having an externalweather-proof casing 70 and an internal casing 72 (see FIGS. 3 and 4). Aterminal stud 74 (FIGS. 3 and 4) extends centrally through each of theterminal bushings 52 and 54, and each stud 74 has threadably secured orclamped thereto a. fixed contact adapter 76.

As shown in FIG. 3, each contact adapter 76 has a fixed contact 80secured to its lower end, with the fixed contact 80 comprising aplurality of contact finger segments 82, which make contact with amovable knife-blade type of movable interrupting contact 84. FIG. 4illustrates the movable interrupting contact 84 in the closed-circuitpo-- sition, making electrical contact with the contact finger segments82. One of the contact finger segments 82 has a portion 86, whichextends below the other finger segments 82 and, since it is the lastportion of fixed contact 80 to break contact with movable contact 84, italways draws the arc 90, as shown in FIG. 3, which ensures that theother finger segments 82 will be maintained in good contacting conditionfor continuous current-carrying capability. Although a knife-blade typecontact structure 84 is shown in FIG. 3, it is to be understood that anysuitable contact arrangement may be employed.

Each pressurized metallic interrupter enclosure 50 includes a pressurechamber, or reservoir 100 maintained in a fixed position withininterrupter enclosure 50 by any suitable means, such as by bolts (notshown) or any other suitable fastening means. A check valve 102 isdisposed in the wall of the pressure chamber 100, which closes when thepressure within the chamber 100 exceeds the pressure outside of thechamber 100 by an amount sufficient to overcome the bias of valvesprings 104. When the pressure differential subsides to a predeterminedpoint, the spring bias opens the valve 102 to allow insulating fluid,such as liquid SP to pass into the chamber '100 from the surroundingregion.

As shown in FIG. 3, a pair of generally U-shaped movable contactstructures 106 and 108, each including a movable interrupting contact 84and a movable pressuregenerating contact 85, are shown supported andsecured to a reciprocally-operable cross-head structure 110. Thecross-head structure 110, shown and described herein, is illustrativeonly, as any suitable operating means for moving the movable contactstructures 106, 108 may be used.

Generally, the cross-head structure 110 includes a spaced pair ofinsulating bars 112, which fixedly clamp the lower portions of 'U-shapedcontact structures 106 and 108. The spaced pair of insulating bars 112are secured to a metallic channel-shaped member 114, which provides apair of raceways 116. Disposed within the raceways 116 are a pair ofdriving rollers 118, secured to the outer free ends of a pair ofrotatable driving cranks 120, pivotally secured on fixed pivot shafts122, and having gear segment portions 124. The gear segment portions 124mesh with a double-sided rack 126, which is disposed at the upper end ofa metallic coupling member 128, which is attached to the upper end ofthe insulating operating rod 48 shown in FIGS. 1 and 2. Openingaccelerating springs (not shown) may be disposed around the couplingmember128 in a well known manner. A metallic bellows 130 may be providedto seal the opening 132 leading into the pressurized enclosure 50.Springs 133 may be used to cushion the movable portion of cross-headstructure when the 'circuit is broken and the cross-head structure 110returns to its fully open-circuit position, as shown in FIG. 3.

An upward opening motion of coupling member 128 causes the crank-arms tobe rotated about their pivot shafts 122 in a direction away from eachother, thereby causing the driving rollers 118 to move outwardly to theouter ends of the raceways 116. The outward movement of the drivingrollers 118 will cause the cross-head structure 110 to move downwardlyto the open position shown in FIG. 3. This establishes twopressure-generating arcs and two serially-related interrupting arcs 90,as will be hereinafter explained in more detail.

A downward opening motion of coupling member 128 causes the crank-arms120 to be rotated in a direction toward each other, which action movesthe driving rollers 118 to the inner portions of the raceways 116,thereby lifting the cross-head structure 110 and causing the movablecontacts 84 and 85 to assume their closed-circuit position shown in FIG.4. This type of cross-head structure arrangement 110 has the advantageof self-alignment and the absence of any lateral forces, which couldresult in jamming. A more detailed description of the mechanicalfeatures and advantages of this type of cross-head arrangement 110 isgiven in United States patent application Serial No. 101,620, filedApril 3, 1961, now US. Patent 3,214,541, issued October 26, 1965, toBenjamin P. Baker, et al., and assigned to the same assignee as thepresent application.

The electrical circuit through interrupter unit 26, shown in FIGS. 3 and4, comprises left-hand terminal stud 74, stationary contact adapter 76,stationary interrupter contact 80, movable interrupter contact 84,connecting portion 138, movable pressure-generating contact 85,relatively stationary pressure-generating contact 146, conducting plate142, relatively stationary pressure-generating contact 146, movablepressure-generating contact 85, connecting portion 138, movableinterrupting contact 84, stationary contact assembly 80, stationarycontact adapter 76 and the right-hand terminal stud 74. Thus, thecurrent path through interrupter unit 26 forms a loop, the benefits ofwhich will be hereinafter described.

The relatively stationary pressure-generating contacts 146 illustrateanother type of stationary contact that may be used, comprising an innerspring-loaded portion 144 and a lower arcing portion 144a. When themovable pressure-generating contact 85 moves from its closed positionshown in FIG. 4, to its open position, shown in FIG. 3, the innerportion 144 followsthe movable contact 85 for a limited distance toallow the arc 140 to be generated at the lower arcing portion 146 andnot at the lower end 144a of the inner portion 144. This keeps thecurrentcarrying contact portion of the relatively stationarypressure-generating contact 144 in good condition.

It will be noted that the generally U-shaped movable contact structures106 and 108 are disposed such that the movable pressure-generatingcontacts 85 enter the pressure chamber 100 through an insulating bushing150, and the movable interrupting contacts 84 are disposed externally ofthe pressure chamber 100. Openings 152 on opposite sides of pressurechamber 100 have directing orifice members 154 disposed therein, withthe orifice members 154 arranged to be adjacent the arcs 90 drawn by themovable interrupting contacts 84, when they move from their closed totheir open-circuit positions.

Arc-splitter means 160 are disposed diametrically opposite the openingsin the orifice members 154. Splitter means 160 include a plurality ofsplitter members 162, which may be formed of polytetrafluoroethylene, orother suitable material, and are designed to surround and contain theare 90, with portions of the splitter members 162 cut away to allow themovable contact 84 to operate without interference with the splittermembers 162. Splitter means 162 provide the high-extinction arc voltagenecessary to interrupt high voltages. It is important to note that thesplitter means 160 are mounted remotely from the interrupting contacts80 and 84, in order to eliminate any solid insulation that might bridgethe gap between contacts 80 and 84 in their open-circuit position. Anisolating gap 164 is maintained between contacts 80 and 84 While theyare in their open-circuit position, thus preventing possible creepageacross solid insulating surfaces. As shown in FIG. 3, the splitter means160 may be mounted on the side walls 166 of tank enclosure 50 by anysuitable securing means.

When the movable interrupting and pressure-generating contacts, 84 and85 respectively, move from the closedcircuit position shown in FIG. 4 totheir opencircuit position shown in FIG. 3, they move downwardly as aunit, and simultaneously establish a pair of pressuregenerating arcs 140within the pressure chamber 100 and a pair of interrupting arcs 90.Because of the loop shape of the electric circuit, the interrupting arms90 are forced by the magntic field to the outside of the loop, and thusmove into engagement with the splitter fingers 162. Thepressure-generating arcs 140 are not affected by the loop shape of theelectric circuit to the degree that the interrupting arcs 90 are,because of substantially equal and opposite magnetic fields produced bythe particular configuration of the loop at its internalpressuregenerating portion. The movement of the interrupting arc 90 isadvantageous in the structure shown in FIG. 3, as when the fluid blastis generated, time will not be lost in moving the are into engagementwith the fingers 162.

As hereinbefore stated, the pressure-generating arcs 140 are produced atsubstantially the same instant that the interrupting arcs 90 areproduced thereby, building up an extremely high pressure within thepressure chamber 100. The fluid 141, such as liquefied SP with-in thepressure chamber 100, under the high pressure, is ejected outwardlythrough the directing orifices 152, as shown by the arrows, and forcesthe arcs 90 between the splitter members 162 of splitter means 160, thuslengthening and cooling the arcs 90 and increasing the arc voltage. Itwill be noted that by arranging the orifices 152 to discharge the highpressure fluid outwardly in diametrically opposite directions, that theresultant reaction upon the pressure chamber 100 is substantially zero.Since these interrupting units are mounted on relatively long supportingcolumns 40, it is important not to generate unbalanced forces. The longmoment arm would produce torques which would be difiicult to braceagainst if unbalanced forces were encountered.

When the arc is extinguished, it cannot reignite due to tracking acrosssolid insulation, as there is no continuous path of solid insulationbridging the contacts 80 and '84. Various metallic portions of theinterrupter and supporting structure near to the contacts may beshielded with arc-resistive material, such as polytetrafiu-oroethylene.For example, tubular member 170 may be formed ofpolytetrafl-uoroethylene to protect the metallic supporting member fromthe action of the interrupting arcs 90.

The interrupting structure shown in FIGS. 3 and 4 is particularlysuitable for use with liquefied gases, although a certain degree ofinterrupting effectiveness is also achieved with an ordinaryarc-extinguishing fluid, such as circuit-breaker oil. Although anynumber of liquefied lgases may be used, singly or in combination, Such38 CO2, S02, SP6, SCFG, SOPZ, CC12F2, C1O3F, C F C F CClF or CF Br, anexceptional performance is obtained with liquefied SP and liquefied SeFas the combination of these two gases is highly effective in arcinterruption and it possesses excellent insulating qualities.

Another embodiment of the invention is shown in FIGS. 5 and 6, with likereference numerals in FIGS. 3, 4, 5 and 6, indicating like components.Generally, the embodiment shown in FIGS. 5 and 6 provides aninterrupting structure 200, which extin-gu'ishes an are 201 due to thedual action of the splitter fingers 202 and the interrupting orifice204. At lower currents the interrupting action is due primarily toorifice action, as sufficient fluid flow will be produced through theorifice 204 to extinguish the are 201 before contact 210 has reached apoint which exposes the splitter interrupter. As the current increases,a point will be reached where the orifice interrupter 204 will bemarginal and pass current zeroes. The are 201 will thus still be ignitedwhen contact 210 reaches its open circuit position exposing the splitter202. The interrupting action will thus be a splitterorifice action,which obtains an interrupting efficiency higher than would be achievedby either the splitter or orifice of interrupters independently. Also,the higher the current to be interrupted, the greater the loop e feet,which forces the are 201 against the splitter 202. Further, theinterrupting assembly 200 provides these advantages without bridging theinterrupting contacts in their open position with solid insulation. Itwill be noted that an isolating gap 206 is maintained between therelatively stationary interrupting contact 208 and the movableinterrupting contact 210. Further, it should be noted that the directingorifice 212, the interrupting orifice 204, and the splitter members 202are all formed in one integral assembly, from polytetrafluo-roethylene,or any other suitable insulating material, th-us greatly simplifyinginstallation, alignment and servicing of the interrupting structure.

More specifically, the embodiment shown in FIGS. 5 and 6 includes apressure-generating tube 214, which may be formed of aluminum, or anyother suitable metallic material, which insures that thepressure-generating tube is at the same floating potential as the casing50 in the open-circuit position of the interrupting unit 26. Thisfeature is claimed in the aforesaid Patent 3,214,541. Although it ispreferable to construct the pressure tube 214 of metal, it may also beformed of an insulating material of sutficient strength to Withstand thepressures enerated.

The pair of U-shaped contact structures 216 and 218 are substantiallythe same as in the embodiment of FIGS. 3 and 4, except the movableinterrupting contacts 210 are shown as being cylindrical in shape,similar to the movable pressure-generating contacts 220. The relativelystationary interrupting contacts 208 include an inner spring-loadedportion 222 which has a limited travel, as shown in the closed-circuitposition in FIG. 6 and in the open-circuit position in FIG. 5, whichallows the fingers 224 to carry the current and the moving portion 222to draw the are. This is silimar to the arrangement for the relativelystationary pressure-generating contacts 230, in which the fingers 232are used primarily for the continuous current carrying function andlower portion 234 for the arcing function, with the arc 240 transferringfrom the spring-loaded central portion 236 to the lower arcing portion234. The surfaces of the contact 230 which draw the arc may be coatedwith an arc-resistant material such as copper-tungsten. The movablepressuregenerating contact 220 may be designed, as shown, to withdrawbelow the upper surface of stationary sealing member 242. Stationarysealing member 242 includes insulating members 243 and 245, as well asan insert 247, constructed of copper-tungsten, or other suitablematerial. Insert 247 prevents the are 240 from burning insulatingmembers 243 and 245.

Relatively stationary pressure-generating contact structure 230 may bedesigned such that the upper connecting portion 244 carries the currentbetween the two contact structures 230, while the pressure-generatingcontacts 230 and 220 are in their closed position, as shown in FIG. 6,and the lower connecting portion 246 carries the arc current during thetime the movable pressure-generating contact 220 moves to itsopen-circuit position shown in FIG. 5.

It should be noted that in the arrangement shown in FIG. 5, that themovable interrupting contacts 210 and the pressure-generating contacts220 enter the pressure generating tube 214, through insulating members250 and 242, respectively, with the movable interrupting contacts 210extending through the opposite side of the pressuregenerating tube 214through insulating member 251. Thus, the interrupting are 201 is drawnexternally of the pressure-generating tube 214, and thepressure-generating arcs 240 are drawn within the pressure-generatingtube 214 to generate pressure therein.

The current path through interrupting structure 26, when it is in itsclosed-circuit position shown in FIG. 6, is from the left-hand terminalstud 74, through contact adapter 76, fixed interrupting contact 208,movable interrupting contact 210, connecting portion 252, movablepressure-generating contact 220, stationary pressuregenerating contact232, connecting portion 244, stationary pressure-generating contact 232,movable pressure-generating contact 20, connecting portion 252, movableinterrupting contact 210, stationary interrupting contact 208, contactadapter 76, and right-hand terminal stud 74. The generally U-shapedmovable contact structure 216 and 218 may be moved vertically by across-head structure 110, as already described in connection with FIG.3, or by any other suitable mechanism.

When cross-head structure 110 moves downwardly, causing the movablecontact structures 216 and 218 to leave their closed-circuit positionshown in FIG. 6, arcs 201 and 240 are generated simultaneously, with thepressure-generating arcs 240, through the liquefied gas 241, which isdisposed within the pressure-generating tube 214, producing an extremelyhigh pressure within the tube 214. The fluid 241, under pressure, isejected through the openings 260, and through the directing orifices 212into the region of the are 201, as shown by the arrows. The fluid movesboth perpendicularly to the are 201, forcing the arc 201 into the ventopenings formed by the interrupting fingers 202, and also moves parallelor axially of the arc through interrupting orifice 204, which aids inextinguishing the are 201 by orifice action. The are 201, by the loopaction hereinbefore described, immediately moves toward the splitters200, and the gas blast forces the arc into the splitter vent openings,lengthening and cooling the arc and increasing the arc voltage. The gasmovement, parallel with the arc, also cools the arc and aids itsextinguishment by the abrupt pressure change due to orifice action. Onceextinguished, isolation gap 206 ensures that there will be no restrikingdue to creepage across solid insulation surfaces. The splitter 200 ismounted remotely from the stationary interrupting contacts 208. In thisinstance, the splitter-orifice assembly is mounted upon thepressuregenerating tube 214.

Once the high pressure within pressure tube 214 subsides, a pressurevalve 262, which closes when the pressure builds up to a predeterminedmagnitude, opens to allow fluid 241 to enter the pressure tube 214 tomake up for the fluid loss by the ejectment of fluid under highpressure. The types of fluids usable in the embodiment shown in FIG. maybe the same as those discussed relative to FIG. 3. Are shields, such asshields 270 and 272, may be constructed of polytetrafluoroethylene and 8disposed to protect metallic surfaces from the efiects of the arcs 201and 240.

Thus, there has been shown and described a new and improved interruptingunit suitable for very high voltages, which provides the advantage ofhigh are voltage without the disadvantage of furnishing creepage pathsacross solid insulation between open interrupting contacts. Also, a newand improved interrupting unit, which combines the high dielectricdisconnect gap of the orificetype interrupter unit with the high arevoltage of the splitter-type interrupter, to provide an interrupter ofhigh efficiency, has been shown and described. In the embodiment of FIG.5, the directing orifice, the interrupting orifice and splitter may beformed in one simple integral assembly, which greatly facilitatesmanufacturing, assembly and maintenance of the interrupter unit.

Since numerous changes may be made in the abovedescribed apparatus, anddifierent embodiments of the invention may be made without departingfrom the spirit thereof, it is intended that all matter contained in theforegoing description, or shown in the accompanying drawings, shall beinterpreted as illustrative, and not in a limiting sense.

I claim as my invention:

1. A circuit interrupter comprising a plurality of interrupting andpressure-generating contacts connected in series circuit relation whichopen and close at substantially the same time to break and complete anelectrical circuit, a pressure chamber, said pressure-generatingcontacts being disposed to break and complete the electrical circuitwithin said pressure chamber and to generate a pressure therein, saidinterrupting contacts being disposed to break and complete theelectrical circuit externally of said pressure chamber, said pressurechamber having opposed side orifice openings with one orifice openingdisposed adjacent each of said interrupting contacts, arc-interruptingmeans including an arc splitter structure disposed adjacent saidinterrupting contacts diametrically opposite the opposed side orificeopenings in said pressure chamber, said arc-interrupting means beingarranged by remote mounting to allow isolation gaps to be producedbetween said interrupting contacts when they are in their open position.

2. A circuit interrupter comprising first and second substantiallyU-shaped movable contact structures each providing a movableinterrupting contact and a movable pressure-generating contact, apressure chamber having two diametrically opposite side orificestherein, a pair of serially-connected stationary pressure-generatingcontacts disposed within said pressure chamber, a pair of stationaryinterrupting contacts disposed externally and on opposite sides of saidpressure chamber adjacent the side orifices in said pressure chamber, apair of interrupting means each including an arc splitter disposedadjacent said pair of stationary interrupting contacts and diametricallyopposite a side orifice in said pressure chamber, the interruptingcontacts of said movable U-shaped contact structures being movable intoengagement with said stationary interrupting contacts, the associatedpressure-generating contact of each U-shaped movable contact structurebeing cooperable with one of said interiorly-located stationarypressure-generating contacts for generating a pressure within saidpressure chamber to provide opposed side fluid blasts out through thetwo side orifices, said pair of arc-interrupting means each beingsecured to a point remote from said stationary and movable interruptingcontacts to allow an isolating gap to be created between said stationaryand movable interrupting contacts when they are in their open position.

3. A circuit interrupter including a casing and comprising first andsecond substantially U-shaped movable contact structures each providinga movable interrupting Contact and a movable pressure-generatingcontact, a pressure chamber disposed interiorly of said casing andhaving two diametrically opposite side orifices therein,

9 a pair of serially-connected stationary pressure-generating contactsdisposed within said pressure chamber, a pair of stationary interruptingcontacts disposed externally of the pressure chamber and adjacent theorifices in said pressure chamber, a pair of arc-splitter means disposedadjacent said pair of stationary interrupting contacts and diametricallyopposite the orifices in said pressure chamber, said pair ofarc-splitter means being secured to opposite side walls of said casing,the interrupting contacts of said movable U-shaped contact structurebeing movable into engagement with said stationary interruptingcontacts, the associated pressure-generating contact of each U-shapedmovable contact structure being cooperable with one of saidinteriorly-located stationary pressure-generating contacts forgenerating a pressure Within said pressure chamber for providing opposedside fluid blasts out of the two side orifices, said pair ofarc-splitter means each being so secured to the side Walls of the casingat a point remote from said stationary and movable interrupting contactsto allow an isolating gap between said stationary and movableinterrupting contacts when they are in their open position.

4. A circuit interrupter comprising an outer casing and a pair ofsubstantially U-shaped movable contact structures disposed therein, eachproviding an interrupting contact and a pressure-generating contact, apressure chamber disposed interiorly of said casing and having two loweropenings for receiving the movable pressure generating contact of eachU-shaped movable contact structure and two diametrically opposite sidefluid-directing orifices therein, a pair of serially connectedstationary pressure-generating contacts disposed within said pressurechamber and cooperable with said movable pressure-generating contacts, apair of stationary interrupting contacts disposed externally of saidpressure chamber but interiorly of said outer casing and cooperable withthe movable interrupting contact of said U-shaped movable contactstructure, said stationary and movable interrupting contacts beingdisposed so that an are drawn between them will be adjacent said sidefluid-directing orifices, a pair of arc-splitter means disposed adjacentsaid stationary and movable interrupting contacts and diametricallyopposite said fluid-directing orifices, said pair of arc-splitter meansbeing secured to the opposed side walls of said outer casing to createan isolating gap free of adjacent solid insulation between saidstationary and movable interrupting contacts when they are in their openposition.

5. A fluid-blast type of circuit interrupter comprising apressure-resistant outer enclosure, a pair of terminal bushingsextending into said outer enclosure, a pair of stationary interruptingcontacts disposed at the interior ends of said terminal bushings, adielectric fluid disposed within said outer enclosure, a pressurechamber having a pair of side fluid-directing on'fices disposed therein,a pair of serially-connected stationary pressure-generating contactsdisposed within said pressure chamber, a pair of substantially U-shapedmovable contact structures each including a movable interrupting contactand a movable pressure-generating contact for engaging said pair ofstationary interrupting contacts and said pair of stationarypressure-generating cont-acts, said stationary and movable interruptingcontacts being disposed adjacent said .pair of side fluid-directingorifices, a pair of tare-splitter means disposed adjacent saidstationary and movable interrupting contacts and diametrically oppositesaid side fluiddirecting orifices, said pair of arc-splitter means beingsecured to the opposed end walls of said outer casing to allow anisolating gap to be created between said stationary and movableinterrupting contacts when in their open position, and means moving saidpair of U-shaped movable cont-act structures simultaneously to establisha pair of serially-related pressure generating arcs within said pressurechamber between said stationary and movable pressure generating contactswhich forces fluid 1% through said pair of side fluid-directing orificesto eflect the extinction in said are splitter means of twoseriallyrelated interrupting arcs drawn between said stationary andmovable interrupting contacts.

6. An electrical circuit interrupter of the fluid-blast type comprisinga first and second set of serially-connected contacts each having astationary and movable contact, a pressure chamber having afluid-directing orifice disposed therein, said second set of contactsbeing disposed to break and complete an electrical circuit within saidpressure chamber and generate a pressure therein, said first set ofcontacts being disposed to break and complete the electrical circuitoutside of said pressure chamber adjacent the fluid-directing orifice insaid pressure chamber, confining arc-interrupter means including an arcsplitter and an interrupting orifice, said are splitter being disposeddiametrically opposite said fluid directing orifice, said interruptingorifice being disposed to allow the movable contact of said second setof contacts to move through the opening in said orifice and draw :an arefrom its associated stationary contact therethrough and interiorly ofsaid confining arc-interrupter means, the pressure generated Within saidpressure chamber by said second set of contacts causing a fluid flow outof the directing orifice into said are splitter and said interruptingorifice, said are interrupter means being secured remotely from saidfirst set of contacts to allow an isolating gap to be produced betweenthe stationary and movable contacts of said first set of contacts whenthey are in their open position.

7. A circuit interrupter of the fluid blast type comprising first andsecond substantially U-shaped movable contact structures each providinga movable interrupting contact and a movable pressure-generatingcontact, a pressure chamber having two diametrically oppositefluiddirecting openings therein, a pair of serially-connected stationarypressure-generating contacts disposed within said pressure chamber, apair of stationary interrupting contacts disposed externally of thepressure chamber and adjacent the fluid-directing openings in saidpressure chamber, a pair of confining arc-interrupting means eachincluding an arc splitter and an interrupting orifice, the movableinterrupting contacts of said movable U-sh-ape'd contact structuresbeing movable through the interrupting orifices of said confining arcinterrupting means and into engagement with said stationary interruptingcontacts, the movable pressure-generating contacts of each of saidU-shaped movable contact structures being cooperable with one of saidinteriorly-located stationary pressure generating contacts forgenerating a pressure Within said pressure chamber for generating afluid blast out of said fluid-directing openings, said pair ofarcinterrupting means each being secured remotely from said stationaryand movable interrupting contacts to allow an isolating gap between saidstationary and movable interrupting contacts to be created when they arein their open position.

8. A circuit interrupter of the fluid-blast type comprising a pair ofsubstantially U-shaped movable contact structures each providing amovable interrupting contact and a movable pressure-generating contact,a pressure chamber having openings for receiving the movableinterrupting and pressure generating contacts, with the movableinterrupting contacts extending completely through said pressurechamber, said pressure chamber also having a pair of fluid-directingopenings for allowing fluid to escape when the pressure in said pressurechamber exceeds the external pressure, a pair of serially-connectedstationary pressure-generating contacts disposed within said pressurechamber and cooperable with said movable pressure-generating contacts, apair of stationary interrupting contacts disposed external to saidpressure cham her and cooperable with the movable interrupting contactsextending through said pressure chamber, said stationary and movableinterrupting contacts being dis posed so that an arc drawn between themwill be adjacent one of the fluid-directing openings in said pressurechamber, a pair of confining arc-interrupting means including an 'arcsplitter and an interrupting orifice, said interrupting orifice beingaligned with one of said movable interrupting contacts such that saidmovable interruping contact moves through said interrupting orifice tomake engagement with said stationary interrupting contact and draws anare back through said interrupting orifice when said movableinterrupting contact moves back to its open position, said are splitterbeing dis-posed such that it is diametrically opposite the directingorifice, with the fluid flow from the directing orifice forcing the arcinto said are splitter, said pair of arc-interrupting means beingsecured remotely from said stationary and movable interrupting contactsto create an isolating gap free of solid insulation between saidstationary and movable interrupting contacts when they are in their openposition.

9. A fluid-blast type circuit interrupter comprising apressure-resistant outer enclosure, a pair of terminal bushingsextending into said outer enclosure, a pair of stationary interruptingcontacts disposed at the interior ends of said terminal bushings, adielectric fluid disposed Within said outer enclosure, a pressurechamber having a pair of fluid-directing openings disposed therein, apair of serially-connected stationary pressure-generating contactsdisposed within said pressure chamber, a pair of substantially U-shapedmovable contact structures each including a movable interruptingcontact, and a movable pressure-generating contact for engaging saidpair of stationary interruptin-g contacts and said pair of stationarypressure-generating contacts, said stationary and movable interruptingcontacts being disposed adjacent said pair of fluid-directing openings,a pair of confining arc-interrupting means including an arc splitter andan interrupting orifice, said interrupting orifice being aligned withone of said movable interrupting contacts with the movable interruptingcontact moving through the interrupting orifice to make engagement withsaid stationary interrupting contact and drawing an are back throughsaid interrupting orifice when said movable interrupting contact movesto its open position, said arc splitter being disposed diametricallyopposite the fluid-directing opening, with fluid flow from the directingopening extinguishing the are drawn between the stationary and movableinterrupting contacts by forcing the are into the arc splitters and byfluid flow through the interrupting orifice, said pair ofarc-interrupting means being secured remotely from said stationary andmovable interrupting contacts to allow an isolating gap to be createdbetween said stationary and movable interrupting contacts when they moveto their open position.

10. A fluid-blast circuit interrupter comprising, in combination, meansdefining a pressure chamber, a U-shaped movable contact structureincluding a movable pressure-generating contact and a movableinterrupting contact, said movable pressure-generating contact beingmovable interiorly of said pressure chamber, a stationarypressure-generating contact disposed interiorly of said presssurechamber and cooperable with said movable pressure-generating contact toestablish a pressuregenerating are within said pressure chamber forestabdishing pressure therein, a stationary interrupting contactdisposed externally of said pressure chamber and coperable with saidmovable interrupting contact to establish an interrupting arc externallyof said pressure chamber, a confining arc-interrupting means includingan arc-extinguishing splitter structure and an orifice structuredisposed adjacent the path of movement of said movable interruptingcontact, fluid-directing means associated with :said pressure chamberfor directing fluid under pressure out of said pressure chamber to forcethe interrupting tare laterally into said arc-extinguishing splitterstructure with a portion of the fluid flowing through said orifice.structure, and means providing a free space between said stationaryinterrupting contact and said confining arcinterrupting means in theopen-circuit position of the interrupter to prevent tracking andcreep-age breakdown in the open-circuit position.

11. A fluid-blast circuit interrupter according to the combination ofclaim 10, wherein two such U-shaped movable conta-ct structures areemployed and the parts duplicated to result in a generally U-shapedcurrent path through the interrupter so that magnetic action assists thefluid-blasting action to drive the two interrupting arcs into the twolaterally positioned splitter structures.

12. A fluid-blast circuit interrupter including an insulatingarc-extinguishing structure for extinguishing an arc,

'said arc-extinguishing structure including an axiallydisposed exhaustorifice means (204) and a laterallydisposed fluid-entrance orifice means(212), contact means including a movable contact rod a'ctuable toWithdraw through said axially-disposed exhaust orifice means (204) andlater-ally past said fluid-entrance orifice means (212), :anarc-splitter structure disposed diametrically on the opposite side ofthe path of movement of said movable contact rod from saidfluid-entrance orifice means, means forcing fluid under pressure throughsaid fluid-entrance orifice means transversely against the establishedarc to force the latter toward said arc-splitter structure, and saidfluid also exhausting out of the insulating arc-extinguish ing structurethrough the axially-disposed exhaust orifice means.

13. The combination of claim 12 wherein means provide a free gap spacebetween the arc-extinguishing structure and the stationary contact ofthe contact means.

14. The combination according to claim 12, wherein a serially-relatedpressure-generating arc provides the fluid flow through saidfluid-entrance orifice means (212).

References Cited by the Examiner UNITED STATES PATENTS 1,934,454 11/1933Spurgeon' 200-150 1,940,120 12/1933 EdSall 200-150 2,081,830 5/1937Merriam 200-150 7 2,228,232 1/1941 Hilliard 200-150 3,091,678 5/1963Leeds 200- X 3,110,791 11/1963 Aspey et al. 200-145 3,214,541 10/1965Baker et al. 200-145 3,214,545 10/1965 Cromer 200-145 X FOREIGN PATENTS850,075 8/ 1939 France.

ROBERT K. SCI-IAEFER, Primary Examiner. ROBERT S. MACON, Examiner.

1. A CIRCUIT INTERRUPTER COMPRISING A PLURALITY OF INTERRUPTING ANDPRESSURE-GENERATING CONTACTS CONNECTED IN SERIES CIRCUIT RELATION WHICHOPEN AND CLOSE AT SUBSTANTIALLY THE SAME TIME TO BREAK AND COMPLETE ANELECTRICAL CIRCUIT, A PRESSURE CHAMBER, SAID PRESSURE-GENERATINGCONTACTS BEING DISPOSED TO BREAK AND COMPLETE THE ELECTRICAL CIRCUITWITHIN SAID PRESSURE CHAMBER AND TO GENERATE A PRESSURE THEREIN, SAIDINTERRUPTING CONTACT BEING DISPOSED TO BREAK AND COMPLETE THE ELECTRICALCIRCUIT EXTERNALLY OF SAID PRESSURE CHAMBER, SAID PRESSURE CHAMBERHAVING OPPOSED SIDE ORIFICE OPENINGS WITH ONE ORIFICE OPEN-